package com.nulldev.util.security.hashing.MD5;

import com.nulldev.util.JVM.JVM;

public class ND5 {
	private static final boolean USE_UPPER_CASE = false;
	@SuppressWarnings("unused")
	private static final String PADDING = "";

	private static String rstr_md5(final String s) {
		return binl2rstr(binl_md5(rstr2binl(s), s.length() * 8));
	}

	private static String rstr_md5(final String s, final int DIV_SIZE) {
		return binl2rstr(binl_md5(rstr2binl(s, DIV_SIZE), s.length() * 8));
	}

	public static String hex_md5(final String s) {
		return rstr2hex(rstr_md5(str2rstr_utf8(s)));
	}

	public static String hex_md5(final String s, final int DIV_SIZE) {
		return rstr2hex(rstr_md5(str2rstr_utf8(s), DIV_SIZE));
	}

	@SuppressWarnings("unused")
	private static boolean md5_vm_test() {
		final String o = hex_md5("abc").toLowerCase();
		JVM.println("got: " + o);
		JVM.println("want: " + "900150983cd24fb0d6963f7d28e17f72");
		return o.equals("900150983cd24fb0d6963f7d28e17f72");
	}

	public static String fromCharCode(int... codePoints) {
		final StringBuilder builder = new StringBuilder(codePoints.length);
		for (int codePoint : codePoints) {
			builder.append(Character.toChars(codePoint));
		}
		return builder.toString();
	}

	private static String rstr2hex(final String input) {
		final String hex_tab = USE_UPPER_CASE ? "0123456789ABCDEF" : "0123456789abcdef";
		String output = "";
		int x;
		for (int i = 0; i < input.length(); i++) {
			x = Character.codePointAt(input, i);
			output += hex_tab.charAt((x >>> 4) & 0x0F);
			output += hex_tab.charAt(x & 0x0F);
		}
		return output;
	}

	private static String str2rstr_utf8(final String input) {
		String output = "";
		int i = -1;
		int x, y;

		while (++i < input.length()) {
			/* Decode utf-16 surrogate pairs */
			x = input.charAt(i);
			y = i + 1 < input.length() ? input.charAt(i + 1) : 0;
			if (0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF) {
				x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
				i++;
			}

			/* Encode output as utf-8 */
			if (x <= 0x7F)
				output += fromCharCode(x);
			else if (x <= 0x7FF)
				output += fromCharCode(0xC0 | ((x >>> 6) & 0x1F), 0x80 | (x & 0x3F));
			else if (x <= 0xFFFF)
				output += fromCharCode(0xE0 | ((x >>> 12) & 0x0F), 0x80 | ((x >>> 6) & 0x3F), 0x80 | (x & 0x3F));
			else if (x <= 0x1FFFFF)
				output += fromCharCode(0xF0 | ((x >>> 18) & 0x07), 0x80 | ((x >>> 12) & 0x3F), 0x80 | ((x >>> 6) & 0x3F), 0x80 | (x & 0x3F));
		}
		return output;
	}

	private static int[] rstr2binl(final String input) {
		int[] output = new int[(((input.length() + 8) / 64) + 1) * 16];
		for (int i = 0; i < output.length; i++)
			output[i] = 0;
		for (int i = 0; i < input.length() * 8; i += 8)
			output[i >> 5] |= (input.charAt(i / 8) & 0xFF) << (i % 32);
		return output;
	}

	private static int[] rstr2binl(final String input, final int DIV_SIZE) {
		int[] output = new int[(((input.length() + 8) / 64) + 1) * DIV_SIZE];
		for (int i = 0; i < output.length; i++)
			output[i] = 0;
		for (int i = 0; i < input.length() * 8; i += 8)
			output[i >> 5] |= (input.charAt(i / 8) & 0xFF) << (i % 32);
		return output;
	}

	private static String binl2rstr(final int[] input) {
		String output = "";
		for (int i = 0; i < input.length * 32; i += 8)
			output += fromCharCode((input[i >> 5] >>> (i % 32)) & 0xFF);
		return output;
	}

	public static int[] binl_md5(final int[] x, final int len) {
		/* append padding */
		x[len >> 5] |= 0x80 << ((len) % 32);
		x[(((len + 64) >>> 9) << 4) + 14] = len; // FIXME: Verify

		int a = 1732584193;
		int b = -271733879;
		int c = -1732584194;
		int d = 271733878;

		for (int i = 0; i < x.length; i += 16) {
			int olda = a;
			int oldb = b;
			int oldc = c;
			int oldd = d;

			a = md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
			d = md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
			c = md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
			b = md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
			a = md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
			d = md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
			c = md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
			b = md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
			a = md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
			d = md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
			c = md5_ff(c, d, a, b, x[i + 10], 17, -42063);
			b = md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
			a = md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
			d = md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
			c = md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
			b = md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);

			a = md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
			d = md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
			c = md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
			b = md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
			a = md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
			d = md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
			c = md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
			b = md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
			a = md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
			d = md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
			c = md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
			b = md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
			a = md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
			d = md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
			c = md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
			b = md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);

			a = md5_hh(a, b, c, d, x[i + 5], 4, -378558);
			d = md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
			c = md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
			b = md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
			a = md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
			d = md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
			c = md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
			b = md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
			a = md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
			d = md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
			c = md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
			b = md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
			a = md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
			d = md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
			c = md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
			b = md5_hh(b, c, d, a, x[i + 2], 23, -995338651);

			a = md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
			d = md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
			c = md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
			b = md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
			a = md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
			d = md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
			c = md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
			b = md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
			a = md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
			d = md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
			c = md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
			b = md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
			a = md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
			d = md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
			c = md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
			b = md5_ii(b, c, d, a, x[i + 9], 21, -343485551);

			a = safe_add(a, olda);
			b = safe_add(b, oldb);
			c = safe_add(c, oldc);
			d = safe_add(d, oldd);
		}
		return new int[]
			{ a, b, c, d };
	}

	private static int safe_add(final int x, final int y) {
		int lsw = (x & 0xFFFF) + (y & 0xFFFF);
		int msw = (x >> 16) + (y >> 16) + (lsw >> 16);
		return (msw << 16) | (lsw & 0xFFFF);
	}

	private static int md5_ff(final int a, final int b, final int c, final int d, final int x, final int s, final int t) {
		return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);
	}

	private static int md5_gg(final int a, final int b, final int c, final int d, final int x, final int s, final int t) {
		return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);
	}

	private static int md5_cmn(final int q, final int a, final int b, final int x, final int s, final int t) {
		return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
	}

	private static int md5_hh(final int a, final int b, final int c, final int d, final int x, final int s, final int t) {
		return md5_cmn(b ^ c ^ d, a, b, x, s, t);
	}

	private static int md5_ii(final int a, final int b, final int c, final int d, final int x, final int s, final int t) {
		return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);
	}

	private static int bit_rol(final int num, final int cnt) {
		return (num << cnt) | (num >>> (32 - cnt));
	}

	public static void main(String[] args) {
		final String o = "2f576c9432231376002798668a930241¤3¤516351532¤4";
		JVM.println(hex_md5(o, 16));
	}
}
